Two sea spiders new to science were hiding 18 metres down off Vancouver Island

Two sea spiders that science had never described were living 18 metres down or shallower in the Salish Sea, close enough to Vancouver Island that divers could reach them on ordinary dives. A University of British Columbia team has now named them Callipallene pilosuspedes and Tanystylum kiixin, the first new sea spiders formally described from the region in nearly a century.

Cormac Toler-Scott, who led the work as part of a master’s degree in zoology at UBC, collected the animals between September 2023 and August 2024. The sites ran from Quadra Island to Vancouver, Bamfield and Victoria, and the deepest dives reached 18 metres, roughly 60 feet. The collection window spans close to a full year of diving, and the sites were spread across several stretches of coastline rather than a single location. Each animal then went through detailed physical examination and genetic sequencing before anyone put a name on it.

Callipallene pilosuspedes and its hairy feet

The first species gets its name from Latin for “hairy feet,” and the hair is the least odd thing about it. According to a ScienceDaily report on the UBC study, the animal has red eyes and a triangular mouth with three lips ringed by sensory tendrils, and it was seen using comb-like appendages to groom itself. Only one specimen of C. pilosuspedes turned up, so everything known about its shape rests on a single animal.

That scarcity matters for how the species can be described. A formal description needs a type specimen, and the team had exactly one, which is why the paper leans on both anatomy and DNA to place it. The paper in Organisms Diversity & Evolution, published on August 26, 2026, lists Toler-Scott with co-authors Eunji Park, Heather Gordon and Brian S. Leander, all affiliated with UBC departments of botany, zoology and earth, ocean and atmospheric sciences.

One animal, then, carries an entire species.

Tanystylum kiixin and the parasites it carries

The second species has shorter legs than its relative, and that design has a cost. Unable to groom effectively, T. kiixin frequently carries parasites and debris on its body. Toler-Scott described the result as “an ecosystem within an ecosystem within an ecosystem,” a phrase that Discover Wildlife quoted to capture an animal that doubles as a habitat for smaller organisms. The paper records that it associates with the hydroid Plumularia setacea.

The name is a different kind of story. Kiixin refers to an ancient Indigenous village site near where specimens were first collected, and the pronunciation, “kee-hin,” imitates the sound of waves at that spot. Popular Science noted that the name honours the village while echoing the shoreline.

Seven species and a key for the Salish Sea

The two new animals are only part of the paper. The authors ran morphological and molecular phylogenetic analyses on seven species in all, redescribing five that were already known: Achelia alaskensis, Achelia gracilipes, Anoplodactylus erectus, Anoplodactylus viridintestinalis and Phoxichilidium quadradentatum. They also supply a dichotomous key to the sea spiders of the Salish Sea and the west coast of Vancouver Island, a tool the region lacked.

Sea spiders are not true arachnids, though they are distant relatives of spiders, scorpions and horseshoe crabs. Popular Science puts their origin at about 500 million years ago and their size range from under half an inch to more than two feet. Most feed through a tube-like proboscis rather than chewing, and some species carry up to 12 legs. The common name is a loose label, since the animals are distant relatives of arachnids and belong to a separate group of marine arthropods.

A near-century gap in the Salish Sea record

A gap of close to a hundred years between new descriptions in a well-travelled stretch of coast says less about the animals than about the effort spent looking. UBC News covered the finding as evidence that small bottom-dwelling animals in the Salish Sea remain poorly catalogued, a problem for anyone trying to track how climate change and human disturbance affect them.

Toler-Scott said more undocumented species likely remain in the area. With a regional key now published and five older species redescribed with genetic data, the next collector has a reference to check a find against, which is the practical gain from a paper whose headline animals are one red-eyed individual and a parasite-covered cousin. Popular Science framed the discovery the same way, as a reminder of how much of the nearby seafloor has gone unexamined even as conservation decisions get made about it, and Toler-Scott’s own expectation that further species are waiting suggests the Salish Sea list is still short. The five redescribed species also gain from the work, since their earlier descriptions now sit alongside molecular data that can settle disputes over identity.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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